Telephone-switchboard.



N0. 638,52l. Patented Dec. 5, I899.

s. MORRISON & T. L. SPRINGER. TELEPHONE SWITCHBOARD.

(Application filed May 19, 1899.)

(No Model.) 3 Sheets-Sheet l.

04 w 1?? WWW m y m: Norms yarns cu. pumo-Lmco'. WASHINGTON bi No. 638,52l. Patented Dec. 5, I899. S. MORRISON &. T. L. SPRINGER.

TELEPHONE SWITCHBOARD.

(Application filed May 19, 1899.) I (,No Model.) 3 Sheets-Sheet 2.

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TELEPHONE SWITCHBUARD.

(Application filed May 19, 1899.)

3 Sh eets-Sheat 3.

=1 fieymoux wmon g/omeg Kma NITED STATES PATENT SEYMOUR MORRISON AN D THOMAS L. SPRINGER,-OF MOOORDSVILLE, INDIANA.

TELEPHONE SWITCHBOARD.

SPECIFICATION forming part of Letters Patent No. 638,521, dated December 5, 1899.

Application filed May 19, 1899. Serial No. 117,426. (No model.)

To all whom it ma concern:

Be it known that we, SEYMOUR MORRISON and THOMAS L. SPRINGER, citizens of the United States, residing at McOordsville, in the county of Hancock and State of Indiana, have invented certain new and useful Improvements in TelephonaSwitchboards, of which the following is a specification.

The object of this invention is the production of a telephone-switchboard having a combined operators cam and self -restoring clearing-out drop, which combined cam and drop is compact in form, self-contained, easily and quickly detached from its connections with the board, and readily replaced in position therein, which is simple and strong in its construction, has no delicate adjustments to become easily disordered, is speedy and accurate in its operation, wherein cross-talk between adjacent lines is eliminated, wherein the calling subscriber does not hear the noise of ringing the called subscriber, and embodying other novel features of advantage to appear later herein.

In the accompanying drawings, Figure l is a diagrammatic sketch illustrating the several electrical connections made in the operation of this opera-tors cam and drop. Fig. 2 is a face view of the operators cam and drop, showing its relative position in the switchboard, also showing in dotted lines the several positions assumed by the cam-handle in the operation of the cam, designating each position by a number. Figs. 3 and i are side views of the cam and drop, taken from oppo site sides thereof, the movable parts being in the relative positions incident to position No. 1 of the cam-handle, as shown in full lines in Fig. 2. Fig. 5 is a rear elevation of the cam and drop, illustrating the means of its attachment to the switchboard and representing the movable parts in positions incident to position No. 1 of the cam-handle, as shown in full lines, Fig. 2, with the drop-plate elevated. Fig. 6 is an under face View showing the electrical connections with the cam. Fig. 7 is a plan view of the cam and drop. Fig. 8 is a view of the cam-shaft removed from the cam-framework. Fig. 9 is an under face View of the bridge-block.

Like letters of reference indicate corresponding parts throughout the several views.

The mechanism hereinafter described isintended to preside over the lines connecting the respective answering-plugs and ringingplugs on telephone-switchboards. The four positions of the cam-handle shown in Fig. 2 imply four sets of connections made by the switches within the cam. That position indicated in the drawings as position No. 1,-

Fig. 2, represents the operators circuit as bridged in on the lines extending to the answering-plug, and therefore presumes the operator to be in communication with the calling subscriber. Position No. 2, Fig. 2, represents the cam as turned to throw the generator-lines into connection with the lines of the calling-plug, whereby the called subscriber is notified by the ringing of his bell. This connection cuts out theanswering-plug lines and the operators circuit. No. 8, Fig. 2, assumes the switches in such relative positions that the plug-lines are made continuous through the operators cam, the operators circuit being cut out, but the magnet for the clearing-out drop included on one of said plug-lines. Position No. 4, Fig. 2, indicates the cam in a position to connect the callingsubscribers lines with those of the generator, whereby the call-bell of the calling subscriber may be rung, the lines of the called subscriber and the operators circuit being cut out.

The clearing-out drop will be actuated by the operation of the hand-generator on the telephone of either subscriber, but only when the plug-lines are continuous through the cam, as assumed by position No. 3, Fig. 2, of the drawings.

In the embodiment of our invention the switchboard is fitted and arranged in substantially the ordinary manner, having the usual jacks connected with subscribers lines occupying the upper portion of the face of the board, with the usual plugs in pairs and the operators cams below, there being in practice one pair of plugs and one operators cam for every ten of the jacks.

At the point of the switchboardAadapted for the reception of the operators cams said board is provided with rectangular openings A in its face, into which openings the cam mechanism is placed, only the hard-rubber face thereof, with the cam-handle and drop, showing on the face of the board.

Transversely across the rear part of the board the supporting-rail A is secured, having opposite each cam the two contact-points A and A for the attachment of the wires of the operators circuit, also having the clamping screw-bolt A Upon this transverse rail A the rear end of the supporting-stem of the cam rests, the screw-bolt A passing through the vertically-slotted end of said stem and through the hard-rubber plate A, bearing the two points A and A? for the attachment of the lines of the generator-circuit.

At the forward end of the stem B of the cam and'on the upper face thereof is secured the cam-framework, composed of the front plate B, the base B the rear upright B and the top cross-bar B In the upper part of this framework an electromagnet is arranged to release the clearing-out drop, the operation of which device will be described later herein. A little below the magnet and extending between the front plate B and the rear upright B of the cam-framework is secured a hardrubber bridge-block B and aflixed to one of its sides are the two contacts B and E the former being one terminal of the winding of the electromagnet. On the opposite side of the bridge-block the contacts B B and B are affixed. The first, B is also a terminal for the end of the coil of the magnet, being the opposite end of said coil from that connecting with contact 13". B merely connects through the strip B with the contact B and B with contact B by means of wire B Two contact-yokes B and B are affixed on the upper face of the bridge-block B their ends extending downward at a little distance from each side of said bridge-block B the ends of the yoke B lying adjacent to the contacts B and B while the ends of the yoke B are adjacent to the contacts B and B The yokes B and B are electrically connected with and fornrterminal contacts for the generator-circuit B. B are contactpoints fixed at the rear upper face of the stem B for making electrical connection with the contacts A and A on the hard-rubber plate A which said contacts A and A are the terminals of the generator-line B Contact-springs C and D are the terminals of the respective lines 0 and D, running, respectively, to the tip 0 and sleeve D of the answering-plug 0 while contact-springs E and F are the terminals of the respective lines E and F, running, respectively, to the tip E and the sleeve F of the ringing-plug E C and 'D are binding-screws for the attachment of the plug-wires G and D, respectively, of the answering-plug O to the stem B of the cam, and E and F are similar means of attachment thereto for the wires E and F of the ringing-plug lines.

C and E are metallic loops for binding the plug-cords to the cam-stem B, relieving the binding-screws from the weight of the plugs, and preventing kinking in said cords.

The contact-springs G and II are the terminals of the operators circuit when said circuit is broken, the lines G and H, extending to the contacts A and A on the rail A forming, with those contacts, a part of said operators circuit.

G2 and H are strips of insulating material secured, respectively, to the springs G and H, on the inner faces thereof, for engagement with the cam, to be later described herein.

The free ends of the contact-springs C, D, E, and F lie normally in touch with the contacts B B B and B", respectively, thus connecting the lines 0 and D of the answering-plug C with the lines E and F of the ringing-plug E including also the winding of the magnet. the contact-springs O and D outward into contact with the yokes B and B the lines 0 and D of the answering-plug O are connected with the lines B of the generator, which latter lines terminate in the said yokes B and B In a similar manner the lines E and F of the ringing-plug may be placed on a circuit with the generator through the contact-springs E and F. The lower ends of all said contact-springs O, D, E, F, G, and H are secured rigidly to the sides of the stem B.

The cam-shaft I, mounted in bearings in the front plate B and the rear upright B of the cam-framework, carries a cam I for engaging the contact-springs G and H and a stud I for moving the said contact-springs E,

and F. The cam I is merely a metallic block of cylindrical form bored out to loosely fit the cam-shaft I, having the two flattened facesI on opposite sides thereof and being provided with the Opening, I extending from its surface to its center, which opening is elongated in the direction of the circumference of said cam and receives a pin or screw I whereby said cam I has a slight oscillatory movement with relation to said shaft I. The stud I is of hard rubber or other non-conducting material and is rigidly affixed to the cam-shaft I. The forward end of the shaft I carries the handle I, fixed thereon, and at the rear end the said cam-shaft has a pin 1 extending through an opening I in said shaft at right angles to its length. This pin 1 is held in position by the set-screw 1 The oscillatory movement of the shaft I is limited bythe stoppins 1 against which the pin 1 impinges.

J is a magnet rigidly secured in the upper portion of the cam-framework and having the armature J pivoted at J to the poles J of the magnet J. The free end of the armature is normally held from contact with the poles J by the action of the flat spring J which, however, the energy of the magnet, when electrically excited, overcomes. The detentarm J 5 is formed integral with said armature and therefore has a slight vertical movement By throwing the free ends of at its free end When the armature is attracted by the magnet.

K is a shaft mounted in hearings in the upper portion of the ca m-framework, having the drop-plate K rigidly affixed by one of the lower corners of said plate to the end of said shaft K. At the rear end of said shaftKand outside the cam-framework is an L-shaped lever rigidly secured to the shaft K, having the stop-arm K and the setting-arm K K are pins which limit the amplitude of the oscillations of the shaft K.

L is the operators circuit and includes both the primary and the secondary thereof. The primary circuit has the operators transmitter, a battery, and the primary winding of an induction-coil, while the secondary circuit includes the operators receiver and the secondary winding of said ind notion-coil.

The operation of a switchboard embodying our invention is as follows: As hereinbefore stated, the normal position of the operators cam mechanism is such that the operators circuit L (including the transmitter and receiver of the operators set) is connected with the lines of the answering-plug C and therefore when a subscriber calls the central station and the said answering-plug is inserted into the jack of said subscribers lines the subscriber and the operator are in circuit. Upon ascertaining the number desired by the calling subscriber the operator inserts the ringing-plug E connected with said answering-plug 0 into the jack on the lines of the called subscriber, at the same time turning the cam-handle 1 to the position designated as position No. 2, Fig. 2. This movement of the cam cuts out the operators circuit L, (contact-springs G and 11,) throwing the contactsprings E and F into touch with the yokes B and B, respectively, turning the current of the generator-circuit B over the called subscribers line and ringing the call-bell upon said subsoribers telephone. The cam-handle I upon being released from this position, No. 2, Fig. 2, returns automatically to position No. 3, Fig. 2, which joins in one circuit the calling and the called subscribers, also including within that circuit the magnet, but leaving out the operators set L. The position indicated as position No. 4:, Fig. 2, is that into which the cam-handle I is turned when it is for any reason desirable to ring the calling subscriber. In this position the contactsprings 'O and D are thrown by the stud 1 into touch with the yokes B and B respectively, connecting the ringing subscribers lines with those B of the generator. As soon as conversation through said telephones is concluded and either subscriber rings off the current thus generated by said act of ringing, passing through the coils of the magnet J, energizes the poles J 3 thereof and attracts the armature J. This movement of the armature raises the detent-arm J from the path of the stop-arm K and permits the drop K to fall by the force of gravitation. This signals the operator that the lines may be disconnected, which disconnection is made by withdrawing the plugs from the jacks into which they were inserted, the operator at the same time turning the cam-handle I to its normal position, (position No. 1, Fig. 2,) cansing the pin 1 to engage the setting-arm K3, throwing said drop upward, in which position it is retained by the falling of the detent-arm J 5 into the path of said stop-arm K Both mechanical and electrical connections between the cam and the switchboard are made by the one act of clamping the stem B to the rail A by means of the screw-bolt A which electrically connects the lines of the generator B and the operators circuit L with their continuing lines within the cam. The lines running to the plugs are connected by attachment to the binding-screws O and D We claim as our invention- 1. In a self-contained operators cam and clearin g-out drop for telephone-switchboards, in combination, a cam-stem answering-plug lines and ringing-plug lines, an operators circuit and a generator-circuit terminating on said stem; a framework on said stem; an electromagnet in said framework; a switch for electrically connecting the pl ug-lines,the electromagnet and said operators circuit, and for electrically connecting either of said pluglines with the generator-circuit an armature for said magnet; a detent on said armature; an annunciator; and means for automatically, mechanically restoring said annunciator by the movement of said switch.

2. In a self-contained operators cam and clearing-out drop for telephoneswitchboards,

'in combination, a cam-stem; answering-plug lines and ringing-plug lines, an operators circuit and a generator-circuit terminating on said stem; a framework on said stein; an electromagnet in said framework; a switch for electrically connecting the plug-lines,the electromagnet and said operators circuit, and for electrically connnecting either of said pluglines with the generator-circuit; an armature for the magnet; a detent on said armature; an annunciator-plate adapted to fall in a substantially vertical plane; and an arm upon said switch for mechanically restoring said annunciator-plate.

3. In a self-contained operators cam and clearing-out drop for telephone-switchboards, in combination, a cam-stem; answering-plug lines and ringing-plug lines, an opera tors circuit and a generator-circuit terminating on said stem; a framework on said stem; an electromagnet and a cam-shaft mounted in said framework; an armature for the magnet; a detent-arm on the armature; an annunciator drop-plate adapted to fall in a substantially vertical plane; a setting-arm for said dropplate; and an arm on said cam-shaft for engaging said setting-arm and automatically, mechanically restoring said annunciatordropplate when the electric circuits are restored.

at. In a self-contained operators cam and IIC clearing-out drop for telephone-switchboards, in combination, a cam-stem; answering-plug lines and ringing-plug lines, an operators circuit and a generator-circuit terminating on said stem; a framework on said stem; an electromagnet and a cam-shaft mounted in said framework; an armature for said magnet; a detent-arm on the armature; an an nunciator drop-plate adapted to fall in a substantially vertical plane; a shaftfor the drop-plate; a stop-arm and a setting-arm affixed to said shaft; and an arm on the cam-shaft for engaging said setting-arm.

5. In an operators cam and clearing-out drop for telephone-switchboards, a single selfcontained structure having, in combination, answering-plug lines and ringing-plug lines; a cam-handle; a magnet; an armature for the magnet; a shaft; an annunciator drop-plate secured, at a point on one of its faces below its center of gravity, to the end of said shaft, which plate is arranged to fall in a plane substantially parallel with the face of the switchboard; a detent for retaining the drop-plate in its elevated position; means for withdrawing the detent; and means comprising said cam-handle for automatically, mechanically restoring said drop-plate.

6. In an operators cam and clearing-out drop for telephoneswitchboards, a single selfcontained structure having, in combination, answering-plug lines and ringing-plug lines; a cam-handle; a magnet; an armature for the magnet; a shaft; an annunciator drop-plate secured, at a point on one of its faces below its center of gravity, to the end of said shaft, which plate is arranged to fall in a plane substantially parallel with the face of the switchboard; a detent for retaining the drop-plate in its elevated position; a source of electrical energy; and means comprising said cam-handle for automatically, mechanically restoring said drop-plate.

7. In an operators cam and clearing-out drop for telephone-switchboards, a singieselfcontained structure having, in combination, answering-plug lines and ringing-plug lines; a cam-handle; a magnet; an annunciatordrop adapted to fall in a plane substantially parallel with the face of the switchboard; means for electrically exciting said magnet, whereby said annunciator-drop is released; and means comprising said cam-handle for automatically, mechanically restoring said annunciator-drop.

8. In an operators cam and clearing-out drop for telephone-switchboards, a single selfcontained structure having in combination, answering-plug lines and ringing-plug lines; circuit changing mechanism comprising a cam-handle; a magnet; an annunciator-drop arranged to fall in a plane substantially parallel with the face of the switchboard; means for electrically exciting said magnet, whereby said annunciator-drop is released; and means comprising said cam-handle for automatically, mechanically restoring said an nunciator-drop.

9. In combination,a telephone-switchboard having an operators cam, which cam comprises circuit-changing mechanism; a camshaft; an electromagnet; an armature for said magnet; a detent-arm rigidly affixed to said armature; an annunciator drop-plate adapted to fall in a substantially vertical plane; a shaft for said plate; a stop-arm and a setting-arm on said shaft; and an arm adapted to be automatically, mechanically operated by the circuit-changing mechanism, adapted to engage said setting-arm.

10. In combination, a telephone-switchboard having an operators cam, which cam comprises circuit changing mechanism; a cam-stem; the lines of an operators circuit and of a generator-circuit on said stem; con tact-points for said lines; corresponding contact-points 011 said switchboard; means for securing said stem to said board; an electromagnet; an armature therefor; a detent-arm on the armature; an annunciator drop-plate adapted to fall in a substantially vertical plane; a shaft for said drop-plate a stop-arm and a setting-arm affixed to said shaft; and an arm arranged to be automatically, mechanically operated by the circuit-changing mechanism, for engaging said setting-arm.

11. In combination, a telephone-switchboard having an operators cam, which cam comprises circuitchanging mechanism; a cam-stem; the lines of an operators circuit and of a generator-circuit on said stem; contact-points for said lines; corresponding contact-points on said switchboard; means for securing said stem to said board; an electromagnet; an armature for said magnet; a detent-arm for said armature; a shaft; an annunciator drop-plate affixed at a point below its center of gravity to said shaft; a stop-arm and a setting-arm also affixed to said shaft; and an armarranged to be automatically, mechanically operated by said circuit-changing mechanism,for engaging said setting-arm.

12. In combination, a telephone switchboard having an operators cam, which cam comprises circuit changing mechanism; a cam-stem having a mortise-slot at its rear end; the lines of an operators circuit and of a generator-circuit on said stem; contact-points for said lines; corresponding contact-points on said switchboard; and means extending through the mortise-slot for securing said stem to said board.

13. In combination, atelephone-switchboardhaving an operators cam, which cam comprises circuit changing mechanism; a cam-stem having a mortise-slot in its rear end; contact-points for the lines of said cam adjacent to said mortise-slot; and means extending through said mortise-slot for securing said operators cam to the switchboard.

14. In combination, a telephone-switchboard having a supporting-rail; an operators IIO circuit; an operators cam, which cam comprises circuit-changing mechanism; a camstem havinga mortise-slot in its rear end; contact-points adjacent to said mortise-slot for the lines of said cam; corresponding contactpoints on the rail of said switchboard, which points on said switchboard are in electrical connection with the operators circuit; aplat-e also having corresponding contact-points for the electrical connection of the lines of the generator-circuit; and a bolt for securing said cam to the said rail.

15. In combination, a telephone-switchboard having a supporting-rail; an operators circuit; answering-plug lines and ringingplug lines; and an operators cam, which cam comprises circuitchanging mechanism; a cam-stem having a mortise-slot in its rear end;

necting said plug-lines with the lines of said 30 cam.

SEYMOUR MORRISON. THOMAS L..SPRINGER. Witnesses:

A. C. MoRaIsoN, T. F. LIsT. 

